BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

This invention relates to latches for securing the position of a door, and more specifically, to a latch which will control a door position according to a predetermined sequence of modes of operations.

DESCRIPTION OF THE RELATED ART A typical vehicle door includes a latch which defines three modes of operation A first mode is a latched mode in which a striker forkbolt is engaged to a striker. A second mode of operation is an open mode of operation in which the striker forkbolt and striker are released and function independently to provide access to a vehicle. A third mode of operation is one in which the striker forkbolt and striker are partially engaged allowing limited motion of a door which has been partially closed or which has been released incompletely from a latched condition to a mode of operation referred to as safety or secondary mode. The sequence of opening a vehicle door in which the door is rotatable abet a horizontally oriented axis such as a deck lid includes a first step of releasing the vehicle door from a latched mode of operation, whereupon a weath ^e rstrip imparts a force against the door causing an upwardly directing motic . thereof. Upon reaching the limit of such displacement, the door returns to a position resting against the weatherstrip, and in some situations, engaging the striker forkbolt and striker sufficiently to reach a safety mode of operation. A vehicle operator inside such a vehicle attempting to open the door will find the door in a safety mode of operation, and consequently impossible to open. Therefore, it is desirable to provide a vehicle door which offers a sequence of operations in which the door is first released from a latched condition to an ajar condition in which no safety mode of operation is available. Subsequent to the ajar condition the vehicle door may then pass to an open position in which the safety mode of

operation is reset and may be utilized upon subsequent attempts to close the door.

SUMMARY OF THE PRESENT INVENTION The present invention includes a device which establishes a sequence for the modes of operation of a door. The sequence is latched, ajar, open and safety. The modes of operation are achieved by the interaction of a striker and a striker forkbolt. The striker forkbolt is secured to the liftgate and the striker is secured to the fixed structure. The striker forkbolt is rotatable about a first axis to various predetermined angular positions. The striker forkbolt may be restricted to various rotational positions to accomplish one of the four modes of operation. A first angular restriction of the striker forkbolt in which the striker forkbolt is engaged with a striker defines the latched mode of operation. A second angular restriction allows unrestricted rotation of the striker catch between the first limit of rotation and a maximum limit of rotation in which the striker forkbolt and the striker may be disengaged upon application of a force attempting to displace the liftgate to an ajar position. A third range of angular positions of the striker catch occurs upon rotation of the striker forkbolt to the maximum limit of rotation whereupon the striker forkbolt and the striker are completely disengaged permitting the door to be positioned in an open mode of operation. The fourth range of angular positions occurs in which the striker forkbolt is restricted to a second limit of rotation in which the striker forkbolt engages the striker defining a safety mode of operation. The invention includes a pawl which is selectively rotatable about a second axis and may be engaged with cooperating abutment surfaces defined on the striker forkbolt to provide various rotational restrictions thereof. The pawl is maintained in a first position engaging a first radially extendinα abutment surface to define the latched condition. The pawl is maintained in a second angularly displaced position which prevents the pawl from engaging the striker forkbolt to define an ajar mode of operation in which the striker forkbolt is free to rotate from the latched condition to a maximum limit of rotation. The pawl is maintained

in a third condition in which the pawl is compliantly urged into contact with the rotatable striker forkbolt to define an open mode of operation. Finally, the pawl is maintained in a fourth condition engaged with a second cooperating radially extending abutment surface of the striker forkbolt to define a safety mode of operation. The preferred embodiment of the present invention includes a first rotatable member engaged with the pawl drivingly engaged to a second member. The second member may be selectively restricted in rotation by an engagement with a third member. Such a restriction of rotation of the second member thereby restricts rotation of the first member defining a displaced position of the pawl which permits the vehicle door to be operated in an ajar condition in which the door will not enter the safety mode of operation until it has been displaced into the position defined by the open mode of operation.

These and other aspects of the present invention will become more readily apparent by reference to the following detailed description of the embodiments as shown in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a structure including a door which is controlled by the apparatus of the present invention;

Figure 2 is a plan view of a first plane of the components of the present invention illustrating the latched mode of operation;

Figure 3 is a plan view of a first plane of the components of the present invention illustrating an ajar mode of operation; Figure 4 is a plan view of the second plane of the components of the present invention illustrating the latched mode of operation;

Figure 5 is a plan view of the second plane of the components of the present invention illustrating the ajar mode of operation;

Figure 6 is a plan view of the first plane of the components of the present invention illustrating an open mode of operation; and

Figure 7 is a plan view of the first plane of the components of the present invention shown in a safety mode of operation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention comprises an apparatus for establishing a mode of operation of a vehicle door 10 as shown in Figure 1 , secured to the fixed structure of an automobile 14 having striker assembly 16 engageable with the apparatus of the present invention 18. The apparatus of the present invention is secured to the vehicle door 10 and is utilized to define and establish various modes of operation of vehicle door 10. The apparatus of the present invention constitutes an assembly of components which may be viewed in various perspectives and for purposes of simplified description will be discussed as viewed in two planes. A first plane of operation may be viewed in Figures 2 and 3 including a striker forkbolt 20 rotatable about a first axis 22. In addition, striker loop 24 is shown engaged to striker forkbolt 20. A pawl 26 rotatable about a second axis 28 includes a radially extending member 30 shown engaged with a cooperating abutment surface 32, thereby defining a restriction of rotation of striker forkbolt 20. This completes the description of the positional inter-relationship of pawl 26 and striker forkbolt 20, defining a latched mode of operation. Figure 3 illustrates the positional inter-relationship of striker forkbolt 20 and pawl 26 to define an ajar mode of operation. As is illustrated, the radially extending member 30 is rotatably displaced to a position which provides no restriction of rotation of striker forkbolt 20. Figures 4, 5, 6 and 7 provide views of the first and second planes of the present invention, illustrating the mechanism which establishes the position of pawl 26 including release lever 34 which is rotatably engaged with pawl 26. Release lever 34 is drivingly engaged with actuator lever 36 which is rotatably secured about third axis 38. A release lever holder 40 is rotatably fixed about fourth axis 42 and defines an abutment surface 44 engageable with cooperating surface 46 of actuator lever 36 to define the ajar mode of operation shown in Figure 5. As previously illustrated in Figure 3, in the ajar mode of operation, pawl 26 is maintained in a position of rotation free from any engagement with striker forkbolt 20 providing unrestricted rotation between a latched mode of operation as shown in Figure 6 and a maximum limit of rotation of striker forkbolt 20 shown in Figure 4. As shown

in Figure 6, release lever holder 40 includes a cam-follower portion 50 which follows a cam profile 51 defined substantially by radius R1 and R2 defined on striker forkbolt 20. Upon rotation of striker forkbolt 20 to an open position as shown in Figure 6, cam-follower 50 is displaced laterally by a dimension equal to R2 minus R1 thereby releasing abutment surface 44 from cooperating abutment surface 46 permitting actuator lever 36, release lever 34, and pawl 26 to be compliantly urged by spring 210 into contact with cooperating abutment surface 32 of radially extending surface 54 of striker forkbolt 20, therein defining an open mode of operation. A final mode of operation, as shown in Figure 7, is defined by the consequence of incomplete closure of door 10, whereupon striker forkbolt 20 engaged with striker loop 24 is partially rotated about first axis 22 such that radially extending member 30 engages with a cooperating abutment surface 32 defined on striker forkbolt 20. The angular restriction of rotation defined by engagement of the respective structures establishes a relative range of rotation of pawl 26 and striker forkbolt 20 which is referred to as the safety mode of operation. Further closing force imposed upon door 10 causes further rotation of striker forkbolt 20 to accomplish the latched mode of operation illustrated in Figure 6. It may be noted that actuator lever 36 can be rotatably displaced from a latched mode of operation to an ajar mode of operation by an actuator establishing a selected position by electromotive force or manually operated cable 60.

One skilled in the art will readily recognize that certain specific details shown in the foregoing specification and drawings are exemplary in nature and subject to modification without departing from the teachings of the disclosure. Various modifications of the invention discussed in the foregoing description will become apparent to those skilled in the art. All such variations that basically rely on the teachings through which the invention has advanced the art are properly considered within the spirit and scope of the invention.